The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Substrate processing systems are used to process substrates such as semiconductor wafers. The processing often involves exposing the substrate in a processing chamber to gas mixtures and/or vaporized precursors. For example only, processes such as chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), atomic layer deposition (ALD), and plasma-enhanced ALD (PEALD) expose the substrate to one or more gas mixtures and/or vaporized precursors when depositing a layer on the substrate.
The vaporized precursors may be generated using a vapor delivery system including a heated ampoule storing liquid and vapor precursor. A push gas source supplies push gas to the ampoule. The push gas flows through the ampoule and entrains vaporized precursor. The push gas and vaporized precursor are delivered to a processing chamber. However, it is difficult and costly to precisely control the amount of vaporized precursor that is delivered to the processing chamber.
Many vapor delivery systems lack real time flow monitoring or direct dose flux measurement. The reduced level of control and/or monitoring leads to unstable deposition rates, defects and film properties that shift due to cycle-to-cycle or substrate-to-substrate dose fluctuation and/or hardware malfunctions.